1. Field of the Invention
The present invention relates to a semiconductor integrated device having a support substrate fastened to at least one surface of a semiconductor chip so as hold resin mixed with microparticles (Filler) between the semiconductor chip and the support substrate, and a method of manufacturing the same.
2. Description of the Related Art
Recently, chip-sized packages (CSP) such as ball grid arrays (BGA) have been widely used in order to reduce the size of chips for implementing semiconductor integrated devices. For example, in order to miniaturize a digital camera that uses a. CCD image sensor, a chip-sized package is adopted in the implementation of the CCD image sensor.
FIG. 8 is a perspective view of one example of a semiconductor integrated device applying a chip-sized package, viewed from the front surface and a rear surface.
First and second support substrates 12, 14 are fastened to the front surface and rear surface of a semiconductor chip 10 using insulating resin 16, 17, and the first and second support substrates 12, 14 not only increase the structural strength of the semiconductor chip 10, but also protect against contamination from the outside. A plurality of ball shaped terminals 18 are provided on an outer surface of the second support substrate 14, and inner wiring of the semiconductor chip 10 and the ball-shaped terminals 18 are connected using external wiring 20. It is possible to establish contact between the semiconductor chip 10 and external elements using the ball shaped terminals 18.
FIG. 9 is a process flowchart for a semiconductor integrated device adopting a chip-sized package. Here, in order to clarify the description, part of a semiconductor substrate 22 is shown expanded schematically. Separate semiconductor integrated circuits 24 divided by a scribe line are formed on the surface of the semiconductor substrate 22. An insulating film 26 such as an oxide film is formed on the semiconductor integrated circuits 24, and inner wiring 28 connecting to wiring inside the semiconductor integrated circuits 24 is arranged on the insulating film 26. The inner wiring 28 is used to achieve contact between the semiconductor integrated circuits 24 and external parts (S10).
Next, a first support substrate 12 is fastened to the front surface of the semiconductor substrate 22 with an insulating resin material 16, constituting an adhesive, interposed between the two. After that, the semiconductor substrate 22 is made into a thin film by subjecting it to a grinding process from the rear surface. Next, etching processing is carried out from the rear surface side of a semiconductor chip 10 along scribe lines dividing the semiconductor integrated circuits 24, to expose the insulating film 26 between adjacent semiconductor integrated circuits 24 (S12).
Next, a second support substrate 14 is fastened to the rear surface of the semiconductor substrate 22 with an insulating resin material 17, constituting an adhesive, interposed between the two, and a laminated body 100 is formed by sandwiching the semiconductor substrate 22 with the first and second support substrates 12, 14. Also, buffer members 32 are provided on the outer surface of the second support substrate at positions where ball-shaped terminals will later be arranged. These buffer members 32 play a cushioning role for softening stress acting on the ball-shaped terminals 18.
Next, using a dicing saw, an inverse V-shaped groove 34 is formed by cutting along the scribe lines from the second support substrate 14 side (S16). The inner wiring 28 of a contact section 30 is also disconnected by cutting, and end sections 36 of the inner wiring 28 are exposed at the inner surface of the grove 34.
A metal film is formed on an outer surface of the second support substrate 14 and the inner surface of the groove 34, and outer wiring 20 is formed by performing patterning of this metal film using a photolithography technique. The outer wiring 20 is patterned so as to connect between end sections 36 of the inner wiring 28 and the buffer members 32 (S18).
Also, a protective film 38 is formed on the outer wiring 20 and ball-shaped terminals 18 are formed on the buffer members 32, and the semiconductor integrated device implemented as a chip-sized package is completed by cutting along the scribe lines (S20).
For example, in the case of adopting a chip-sized package in a CCD image sensor, since the semiconductor integrated device 24 side is a light-receiving surface, a transparent material such as glass having high optical transmittance is used at least in the first support substrate 12. Epoxy resin or the like having high transmittance can also be used in the insulating resin for fastening the first support substrate 12 and the semiconductor chip 10.
On the other hand, in the case of using an organic material such as epoxy resin in the insulating resin 17 for fastening the second support substrate 14, stress is generated between the insulating resin 17 and the semiconductor substrate 22 due to different thermal expansion coefficients. As a result, problems arise such as twisting of and degradation in the characteristics of the semiconductor chip 10. For this reason, filler having grains, such as silicon dioxide (SiO2) or magnesium oxide having a lower thermal expansion coefficient than an organic material (microparticles) is mixed in with the insulating resin 17 for fastening the semiconductor chip 10 and the second support substrate 14, to make the overall thermal expansion coefficient consistent with the thermal expansion coefficient of the semiconductor substrate 22.